Severe hyperkalaemia is a life threatening electrolyte abnormality that if not treated urgently, might cause electric death. Hyperkalaemia induced electrocardiogram (ECG) alterations vary according to the levels and rate of increase of potassium concentration ([K(+)]) in the extracellular milieu but the paradox is that not all these cases provide ECG changes. We describe the first case in the literature of transient sinus rhythm (SR) recovery despite severe hyperkalaemia in a 57-year-old (yo) male patient with impressive ECG changes considering the heart rhythm and QRS morphology. We also review the literature for the mechanism of ECG alterations induced by hyperkalaemia.